How to power the NRF52 chip as standalone (without the DK)?

[Marcel]

Hi guys,

I have the NRF52-DK and want to power only the NRF52. So basically, I want to power it over VDD_nRF.

When I power my DK with a battery and then measure my current consumption with a power analyzer (agilent power analyzer n6705b) with the nrf current measurement pins, the current is about 20uA (which is fine).

When I tried to power it over Vdd_nRF with the power analyer as a 2-Quadrant-Power Supply, I get like 8mA...

Is there a way to get right measurements?

[Stian Røed Hafskjold]

The easiest way is to power only the VDD_nRF domain and short VDD to GND. Then you will also have to disconnect the debugger from the chip, as it will hold the reset line and SWDIO low.

Step-by-step process:

1. Open SB9
2. Cut SB27 (reset)
3. Cut SB20 (SWDIO)
4. Connect VDD to GND using P1 header
5. Power chip with P22 (or P20) header. Positive on VDD_nRF side, and negative on VDD/GND side.

If you want to flash the chip later using the on-board Jlink, you need to short SB20 again. It's enough to just short it with a screwdriver or similar when you flash. Alternatively you can use the 'debug in' header with an external debugger (or another nRF5 DK).

I've only tested this on v1.1.1 of the PCA10040 DK, so the steps might vary a bit on other versions of the board, but the principle should be the same.

Remember that this bypasses any of the reverse voltage protection diodes, so by doing anything wrong here (i.e. negative on VDD_nRF and positive on VDD/GND) you might brick the chip.

[Marcel]

Hi, thanks for the answer. I already bought a breakout board to test. When I decide to change the DK, I will post my experience.